Blood vessel constriction and GTN

 Homeostasis refers to the body’s ability to maintain a stable internal environment. Factors such as hormones, temperature and water content in the body need constant balancing.  Constricting and dilating the blood vessels is one of the main mechanisms employed by the body to help achieve a state of inner equilibrium.

By either limiting the blood flow to certain organs, or by allocating extra blood flow to certain organs, the body manages its resources accordingly. When you squeeze the opening of a garden hose pipe, the water coming out would squirt out with additional force. Less water would be exiting the hose as well and one could limit the outflow by tightening the hose. Likewise, constriction of blood vessels, also known as vasoconstriction, is when the blood vessels tighten, in order to make the opening smaller. When the blood vessels relax in order to make the opening wider, it is known as vasodilation.

In a healthy person, vasoconstriction may occur to stabilize blood pressure or raise blood pressure and control how blood is distributed throughout your body. For example, when a motor vehicular accident victim bleeds profusely, the blood pressure drops due to blood volume loss. To make up for the falling pressure, the blood vessels constrict, so that the pressure is maintained, even if the volume of blood has decreased. Vasoconstriction also occurs to conserve body heat in cold temperatures, to send more nutrients and oxygen to organs that need them the most, and to protect your body against blood and fluid loss.

On the other hand, abnormal vasoconstriction can also occur due to narrowing of blood vessels secondary to deposition of fat layers in. This reduces the diameter and contributes to pathological vasoconstriction.  This can occur in diseases such as hypertension (high blood pressure). Blood vessel narrowing may also be a side effect of drugs, and foods such as caffeine and salt. Foods high in salt add stress to the circulatory system by making them constrict, thereby contributing to high blood pressure. 

Without medical intervention, the effects of chronically narrowed blood vessels will end up placing a burden on the circulatory system, and ultimately, the heart is affected. Untreated high blood pressure (hypertension) can also lead to vision loss and stroke over time.

Vasodilators, are drugs that cause the blood vessels to dilate, and these substances are useful when dealing with the effects of vasoconstriction, especially in hypertensive patients and other heart patients, in whom pathological vasoconstriction occurs. 

Glyceryl trinitrate, or GTN, is a type of medicine called a nitrate. It is used to treat angina (chest pain). 
Pain associated with angina develops if part of your heart muscle does not get as much blood and oxygen as it needs. It is usually caused by narrowing of your coronary arteries due to a build-up of a fat. The narrowing makes it more difficult for blood to flow to your heart muscle. GTN works in two ways. It relaxes blood vessels in your body causing them to widen, and this reduces the strain on your heart, making it easier for your heart to pump blood around your body. It also relaxes and widens blood vessels in your heart (coronary arteries), which increases the flow of blood to your heart muscle.

GTN tablets and spray are used under your tongue. The medicine is absorbed into your body faster this way. Heart patients suffering from angina must make sure GTN is within their reach at all times, and those who are still silently suffering should speak to their physicians for more advice and insight on GTN use and if this medicine would benefit them.